Heretofore the only commonly used methods for removing vascular occlusive lesions involved either the use of balloon catheter techniques or direct local surgical removal. Balloon catheter systems are cited in the medical literature to remove non-adhered embolic material. The limiting disadvantage of this system being the inability to remove structurally adhered material without inherent damage to the vessel wall and the distal release of fragmented lesion material causing tissue damage and loss of viability. Local surgical removal involves cutting through several layers of viable tissue or the invasion of major body cavities to reach the involved stenotic or occluded vessel. Not only does this involve the possibility of infection, pain, and loss of viable tissue, but also an increased risk of mortality. Another major disadvantage is the increased financial burden of major invasive surgery.
After a thorough search of the patent literature, several different instruments have been proposed in an unsimilar fashion to perform a similar type of function as is being set forth in this invention. It is unknown to date if any of these instruments has been reduced to common surgical practice of a clinically useful nature. Also listed in the patent literature are three inventions that have similar physical characteristics to the Transluminal Lysing System, but do not involve the same inventive concepts. The first of these is U.S. Pat. No. 2,944,552 "Surgical Instrument" issued to J. A. Cannon. This instrument is similar to the radial cutting cannula portion of the Transluminal Lysing System but has no provisions for the holding and removal of excised material. Another is U.S. Pat. No. 3,683,891 "Tissue Auger" issued to Eskridge and Wilson for the removal of core shaped biopsy samples of living tissue. The "Tissue Auger" provides no means for holding excised material under dynamic blood flow conditions. It also implies only two modes of cutting action. The Tissue Auger does not provide a smooth cutting surface and action and would therefore create torsional resistance in the excision process which is a disadvantage when working intraluminally. The Tissue Auger would not be likely to negotiate intraluminal passages without damage to the luminal walls if used in a vascular lumen. The third invention is U.S. Pat. No. 4,030,503 "Embolectomy Catheter" issued William T. Clark and is similar to the Transluminal System but provides only one cutting mode. Embolisms are usually not adhered to the lumen wall and can be removed more easily than adhered deposits. Use of an Embolectomy Catheter in an adhered deposit, as described in the above mentioned U.S. Pat. No. 4,030,503, may cause severe luminal damage or vessel rupture if the lesion is removed without complete excision prior to removal.
All three of the above mentioned instruments although similar to the Transluminal Lysing System are, to our knowledge, used under very unsimilar circumstances to remove unsimilar material from the body and as patented would not be useful in the removal of stenotic and occlusive adhered lesions of a vascular lumen.
Field of Search:
United States Classifications 128/303,303.1, 304,305.
References:
______________________________________ 812,020 "Embalming Catheter" Crippen 843,951 "Gape Worm Extracter" Klock 2,850,007 "Biopsy Device" Lingley 2,994,552 "Surgical Instrument" Cannon 3,683,891 "Tissue Auger" Eskridge; Wilson 3,811,446 "Erdarterectomy Apparatus" Lerwick 4,020,847 "Rotating Cutting Catheter" Clark 4,030,503 "Embolectomy Catheter" Clark 4,207,874 "Laser Tunneling Device" Choy 4,290,427 "Endarterectomy Apparatus" Chin 4,273,128 "Coronary Cutting and Dilating Lary Instrument" 4,315,511 "Endarterectomy Apparatus" Chin 4,445,509 "Method and Apparatus for Removal of Auth Enclosed Abnormal Deposits" ______________________________________